The objective of the research is to examine the physicochemical basis of DNA-protein interactions with a focus on the mechanism of action of the enzymatic and binding proteins involved in replication, recombination and transcription. Specific objects of study will be the gene-5 protein from the filamentous bacteriophage fd (involved in final replication and packaging of the DNA), the gene-32 protein from T4 (involved in recombination), the DNA melting protein from E. coli (presumably involved in replication) and the phage-coded RNA polymerase from T7. By a combination of chemical modifications and physical probes it should be possible to determine changes in the conformation of the protein on binding, the functional residues involved in binding, and ultimately the structure of the complex. The physical probes to be used are circular dichroism (CD), F19-NMR of DNA-binding proteins labelled with fluorotyrosine or fluorophenylalanine and the complexes of these derivatives with deoxynucleotides, electron spin resonance (ESR) of transition metal ion probes, and X-ray diffraction and low angle scattering of the DNA-protein complexes. Isolation of restriction fragments of the DNA-template carrying promoter regions for T7 RNA polymerase will be attempted.